FR2937077A1 - COMPONENT FOR DRILLING AND OPERATING HYDROCARBON WELLS - Google Patents

Abstract

The subject of the invention is a component used for drilling and operating hydrocarbon wells, of substantially tubular shape, having a first end (200; 100) connectable to a second end (100; 200). ) another component also used for drilling and operating hydrocarbon wells, the first end (200; 100) having an end portion (210; 110) having a first abutment surface (211, 201); 111, 101) adapted to cooperate in clamping with a corresponding abutment surface (101, 111; 201, 211) of the second end (100; 200) and having a sealing surface (212; 102) adapted to cooperating in clamping with a corresponding sealing surface (102; 212) of the second end (100; 200), said end portion (210; 110) being preceded by a threadable zone (220; 120) adapted to be screwed in a corresponding threaded zone (120; 220) of the second end (100; 200), characterized in that a compressible volume (214a, 214b) is provided in the thickness of the first end portion (210; 110) and partly under the sealing surface (212; 102), so as to reduce the radial stiffness of said terminal portion by at least 20%, while retaining at least 60% of the axial stiffness.

Description

The present invention relates to a component used for the drilling and exploitation of hydrocarbon wells, and more specifically the end of such a component, said end being of male or female type and adapted to be connected to a corresponding end of another component also used for drilling and exploitation of hydrocarbon wells.

By component used for the drilling and the exploitation of the hydrocarbon wells, any element of substantially tubular form intended to be assembled with another element of the same type or not to constitute in fine is a lining able to drill a well of hydrocarbons, either an underwater riser for maintenance such as work over risers, or a column of casing or production of large thickness involved in the operation of the well. The invention is particularly applicable to components used in a drill string such as for example Drill Pipes, Heavy Heavy Drill Pipes, Drill Collars, and Rod and Stem Connection Parts. heavy say the tool joint.

In known manner, each component used in a drill string generally comprises one end provided with a male threaded zone and one end provided with a female threaded zone each intended to be assembled by screwing with the corresponding end of another component. , the assembly defining a connection. The lining thus formed is rotated during drilling at the surface of the well; therefore the components must be screwed together with a large torque to be able to transmit a sufficient torque to allow drilling in the well without there being unscrewing or over-screwing.

The tightening torque is generally achieved by cooperation in clamping abutment surfaces provided on each of the components to be screwed.

Also known, pressurized sludge circulates inside the drill string to the bottom of the well so as to ensure the proper operation of the drill bit and so as to bring the debris to the surface.

However, under certain conditions of drilling or using connections, gas may be under pressure. The sealing thus far guaranteed by abutment surfaces is then no longer ensured. Also, it is necessary to ensure a higher level of sealing and corresponding to high pressures at the connection between two components. To do this, it is known, on other types of connections such as VAM TOP connections described in the catalog No. 940 of the plaintiff, to spare the male end of the connection, beyond the threaded zone , a sealing surface intended to cooperate in radial clamping with a sealing surface formed on the female end of the connection. More specifically, the clamping cooperation between the two surfaces is effected by the force-fitting of the sealing surface of the male end under the sealing surface of the female end, and this, during assembly of the screw connection. In order to facilitate the mounting in force, it is known, for example, to use frustoconical sealing surfaces on each of the male and female ends.

However, given the evolution of current specifications that tend to require seals compatible with very high pressures, it is necessary to impose high contact pressures at the sealing surfaces, these contact pressures being achieved by interference between the male element and the female element. By interference is meant the difference between the average diameter value of the portion carrying the sealing surface of the male end prior to force mounting, and the average diameter value of the portion bearing the sealing surface of the male end once it is caught in the female end.

Given the thicknesses of the components used in a drill string that are in the range of 12.7 to 63.5 mm (0.5 to 2.5 inches) according to the dimensional specifications required by the API 7 standard, which is the standard defined for the components of drilling by the American Petroleum Institute, then raises the problem of seizure during the force assembly, said seizure being a function of the value of the contact pressure and therefore the interference and the thickness of the component. The same problem arises for connections for Work Overiser High Pressure or for thick casing or production tubes.

To reduce the risk of seizure, several solutions have been considered. A first avenue of improvement, to reduce interference, has been studied. It then appeared that it is incompatible with the permissible machining tolerances. Indeed, it should limit the maximum permissible deviations and concentric defects of the average diameter of the portion carrying the male sealing surface while maintaining the seal.

A second way of improvement has been to reduce interference while extending the sealing surface. However, it appears during the tests, that lengthening the length of contact between the two sealing surfaces increases the instability of said contact, and therefore can induce a loss of tightness under certain operating conditions.

Therefore, the object of the invention is to overcome the problem of seizing sealing surfaces by decreasing mainly the radial stiffness of the portion carrying the male sealing surface without losing too much axial stiffness.

More specifically, the subject of the invention is a component used for the drilling and exploitation of hydrocarbon wells, of substantially tubular shape having a first end that can be connected to a second end of another packing component. the first end having an end portion having a first abutment surface adapted to cooperate in clamping with a corresponding abutment surface of the second end and being provided with a sealing surface adapted to cooperate in clamping with a corresponding sealing surface of the second end, said end portion being preceded by a threaded zone adapted to be screwed into a corresponding threaded zone of the second end, characterized in that a compressible volume is formed in the thickness of the first end portion and partially under the sealing surface, so as to reduce the radial stiffness of said po at least 20%, while retaining at least 60% of the axial stiffness.

According to certain features, the compressible volume consists of at least one recess formed in the thickness of the end portion. According to other features, the at least one recess encroaches on at most 50% of the first abutment surface.

According to other features, the recess is a groove of substantially annular shape, and axisymmetrical along the axis of revolution of the component.

According to other features, the recess is a groove opening at the first abutment surface.

According to other features, the length of the groove is chosen so that it extends under at least 75% of the sealing surface.

According to other features, the groove has a thickness of between 10 and 40% of the minimum thickness of the zone carrying the sealing surface. According to other features, the compressible volume is a groove opening inside the terminal portion.

According to other features, the length of the groove is chosen so that it extends under at least 75% of the sealing surface.

According to other features, the groove has a depth of between 10 and 40% of the minimum thickness of the zone carrying the sealing surface.

According to other features, the compressible volume consists of an annular recess opening inside the terminal portion and at the abutment surface, partially filled by a reinforcement.

According to other features, the reinforcement has an axial Young's modulus greater than the Young's modulus of the material forming the drill string.

According to other features, the reinforcement has a coefficient of friction at the level of the abutment surface which is at least 20% greater than that of the material comprising the drill string. According to other features, the end portion includes an appendage extending after the sealing surface to the abutment surface.

According to other features, the first end of the component comprises a second abutment surface adapted to cooperate in clamping with a corresponding abutment surface of the second end.

Other advantages and features of the invention will appear in the following detailed description by way of non-limiting examples and in the appended drawings, which may therefore not only serve to make the invention better understood but also contribute to its definition where appropriate.

Figure 1A shows an axial sectional view of a component of a drill string according to a first embodiment. Figure 1B shows a detailed view of the component according to the first embodiment.

Figure 2A shows an axial sectional view of a component of a drill string according to a second embodiment.

Figure 2B shows a detailed view of the component according to the second embodiment.

Fig. 3A shows an axial sectional view of a component of a drill string according to an improvement of the first embodiment.

Figure 3B shows a detailed view of the component according to this improvement. Figure 4A shows an axial sectional view of a component of a drill string according to a variant of the first embodiment.

Fig. 4B shows a detailed view of the variant component of the second embodiment. Figure 5 shows comparative results between the prior art, the first embodiment of the invention and its improvement. The references used for each of the identical figures.

According to the invention and as shown in Figures 1A, 2A, 3A, there is shown a connection between the rods of a drill string having a substantially tubular shape. The connection is conventionally composed of a component having a male end 200 called male tool-seal and a component with a female end 100 called female tool-seal, the male end 200 being able to be connected to the female end 100. The end 200 comprises an end portion 210 terminated by an internal abutment surface 211 adapted to cooperate with a corresponding abutment surface 101 of the female end 100. The end portion 210 also comprises a surface sealing member 212 adapted to cooperate in clamping with a corresponding sealing surface 102 of the female end 100. The sealing surfaces 212, 102 are conventional sealing surfaces of the technical field considered. They may also be cone-cone or torus-on-cone sealing surfaces or torus and cone-cone as described in WO03 / 048623 or WO04109173. The end 200 also comprises a male threaded zone 220 adapted to be screwed into a corresponding threaded zone 120 of the female end 100, which precedes said end portion 210. The threaded zones 220, 120 are conventional threaded zones of the technical field considered. .

According to the invention, a compressible volume is made in the thickness of the end portion and in particular under the sealing surface, so as to reduce the radial stiffness of said end portion by at least 20%, while retaining at least 60% of the axial stiffness.

Advantageously in terms of embodiment, the volume 214a, respectively 214b, is a recess formed in the thickness of the end portion 210, so that said end portion 210 is more flexible when a force is applied perpendicular to the 300 axis of the male end.

The recess is also designed so that it encroaches on at most 50% of the abutment surface 211. Thus, it preserves the axial stiffness of said end portion so that the stop plays its role during the screwing of the male ends and female.

According to a first embodiment described and detailed in FIGS. 1A and 1B, the recess is a groove 214a of substantially annular shape, and symmetrical about the axis of revolution 300 of the male end 200. The groove 214a opens at the level of the internal abutment surface 211. Those skilled in the art will know how to size the groove 214 a, in particular in terms of the length L, of the thickness ev, and of the radial distance from the groove with respect to the sealing surface 212, so as to reduce the radial stiffness of the end portion 210 by at least 20%. It appears in particular that the distance of the groove with respect to the sealing surface 212 is also a parameter which influences the radial stiffness.

Preferably, the length L of the groove 214a is chosen so that it extends at least 75% of the sealing surface 212. Likewise, the groove 214a has a thickness of between 10 and 40% of the minimum thickness of the zone carrying the sealing surface 212.

By way of example, a finite element model gives the so-called surface equation equation connecting the contact force F at the area 212 as a function of the length L and the thickness ev: In this example, the groove is formed in the middle of the end so as to be equidistant from the inner and outer periphery of the end 210.

F = a + be, + cL + d Lev + eev2 + fL2 + gLev2 + hevL2 + iL2e, 2

a, b, c, d, e, f, g, h, i, being finite element coefficients and functions of the dimensional characteristics of the drill string. Thus, for a thickness e of the end 210 equal to 12 mm and for a groove thickness e equal to 4 mm and a length L equal to 12.5 mm, a force F equal to 1603498 Newtons is obtained. Knowing that without groove 214a, a force F equal to 2158847 Newtons is obtained, thus achieving a decrease of more than 25%. Moreover, by limiting e to 4 mm or 33% of es, the reduction of the axial stiffness is minimized insofar as the reduction of the abutment surface 211 is minimized. Of course, for a component of given geometry and for a groove whose dimensions are fixed, it is possible to increase or decrease the radial stiffness respectively approaching or moving away from the sealing surface 212, and without varying the axial stiffness. According to a second embodiment described and detailed in FIGS. 2A and 2B, the recess is a groove 214b of substantially annular shape and symmetrical about the axis of revolution 300 of the male end 200. The groove 214b opens at Within the terminal portion 210. the skilled person will size the groove 214b, especially in terms of length L, thickness so as to reduce the radial stiffness of the end portion 210 by at least 20%. %.

As with the first embodiment, the length L of the groove 214b is preferably chosen so that it extends at least 75% of the sealing surface 212. Likewise, the groove 214b has a thickness ev, between 10 and 40% of the minimum thickness es of the zone carrying the sealing surface 212. A calculation also based on the finite elements makes it possible to establish an equation similar to that corresponding to the previous embodiment, either :

F = a '+ b'ev, + c'L + of LeV, + ee, 2 + f'L2 + g'Leä, 2 + h'e ,, L2 + i'L2ev,

a ', b', c ', d', e ', f', g ', h', i 'being finite element coefficients and functions of the dimensional characteristics of the drill string.

In addition, since the groove does not impinge on the abutment surface 211, the axial stiffness is largely maintained.

According to a third embodiment described and detailed in FIGS. 3A and 3B, the annular recess 214a is filled by a reinforcement 215, and this partially so that only a space of thickness ev, 'is provided between said reinforcement and the inner surface of the end portion 210. Due to the presence of the thickness ev 'of the space formed between said reinforcement and the inner surface of the end portion 210, a reduction in the stiffness of the portion carrying the surface is obtained. 212, and this as in the embodiments described above. Moreover, thanks to the reinforcement 215 which extends to the internal abutment surface 211, the axial stiffness of the end portion 210, which was affected by the recess 214, is increased.

The reinforcement may be attached to the end 200 by any means such as, for example, screwing, crimping, gluing, welding, brazing.

Advantageously, the reinforcement 215 has a Young's modulus greater than that of the material constituting the connection. Thus, the reinforcement 215 significantly increases the axial stiffness of the end portion 210 carrying the internal abutment surface. Thus, the tightening torque applied between the abutment surface 211 and the corresponding surface 101 can be increased. For example, it is possible to use tungsten carbide or resins loaded with carbon fibers.

Advantageously, the reinforcement 215 has a coefficient of friction at the level of the abutment surface 211 at least 20% greater than that of the material forming the drill string, so that it acts as a brake capable of countering the unscrewing of the packing components during drilling. For example, the abutment surface 211 may be treated in order to increase the coefficient of friction, or to perform a metal deposition of the Cupro-nickel type. The invention finds an advantageous application in the case where the portion carrying the sealing surface 212 is extended by an appendage 213 thus extending after the sealing surface 212 to the internal abutment surface 211. This type In particular, the device used to move the sealing surfaces away from the abutment surface has the characteristic of reducing the axial stiffness of the end 210.

According to still other embodiments, the drill string component comprises an external abutment surface 201 capable of cooperating in clamping with a corresponding abutment surface 111 of the female end 100. This external abutment surface makes it possible in particular to increase the tightening torque.

In the case where a sealing surface would be formed between the outer stop and the threaded zone 120, 220, and as described in FIGS. 4A and 4B, it is of course conceivable to apply the principles of the invention described above. . More specifically, it would be appropriate for example to provide in the end portion 110 of the female end 100 a groove of substantially annular shape, and symmetrical along the axis of revolution 300 of the female end 100. The groove may be conformed for example to one of the embodiments described above.

In summary, the invention can be applied both to a component having an internal stop surface 211 or external 201, to a component having two abutment surfaces, one being internal and the other being external. In the latter case, it appears that the connection between the components connected in a complementary manner can show two sealing zones each cooperating in contact sealing two sealing surfaces. The invention thus makes it possible to solve the problem of seizing generated by the sealing zones by decreasing the radial rigidity as appropriate at the level of the end portions (210, 110) while maintaining the axial rigidity of the abutment surfaces (211, 111).

The components are dimensioned, in the case where there is an internal stop and an external stop, so that the docking is done first at the internal stop or at the outer stop.

FIG. 5 firstly presents a comparison relating to the permissible radial interference 8, that is to say the maximum interference that it is possible to obtain while remaining below the Hertz Pmax pressure from of which seizing occurs, with DO corresponding to a connection of the prior art, D1 corresponding to a connection according to the first embodiment of the invention and D3 corresponding to a connection according to the improvement of the first embodiment of the invention. The invention is described in FIGS. 3A and 3B. It is clear that the embodiments D1 and D3 make it possible to increase the radial interference 8 considerably. As a result, the seal is optimized. FIG. 5 also shows that the first embodiment does not significantly affect the permissible tightening torque C with respect to the results of the prior art and that the third embodiment even allows to increase it.

According to other embodiments of the invention not shown in the figures, the compressible volume formed under the sealing surface may be materialized by a plurality of grooves 214a or 214b machined in the end portion of one end of a component used for drilling and exploitation of hydrocarbon wells. The component can of course be a lining component capable of drilling a hydrocarbon well such as the connection parts of the rods and heavy rods called the tool joint. It can also be a subsea riser component for maintenance such as workoveriser, a casing column component or heavy-gauge production involved in the operation of the well.15

Claims (16)

REVENDICATIONS1. A component for drilling and operating hydrocarbon wells of substantially tubular shape, having a first end (200; 100) connectable to a second end (100; 200) of another component also used for drilling and operating hydrocarbon wells, the first end (200; 100) having an end portion (210; 110) having a first stop surface (211, 201; 111, 101) adapted to cooperating in clamping with a corresponding abutment surface (101, 111; 201, 211) of the second end (100; 200) and being provided with a sealing surface (212; 102) adapted to cooperate in clamping with a surface sealing member (102; 212) corresponding to the second end (100; 200), said end portion (210; 110) being preceded by a threaded zone (220; 120) adapted to be screwed into a threaded zone (120; 220) corresponding to the second end (100; 200), characterized in that a compressible volume (214a, 214b) is provided in the thickness of the first end portion (210; 110) and partly under the sealing surface (212; 102), so as to reduce the radial stiffness of said terminal portion by at least 20%, while retaining at least 60% of the axial stiffness. 2. Component according to the preceding claim, characterized in that the volume (214a, 214b) consists of at least one recess formed in the thickness of the end portion (210; 110). 3. Component according to claim 2, characterized in that the at least one recess (214a, 214b) encroaches on at most 50% of the first abutment surface (211; 111). 4. Component according to any one of claims 2 or 3, characterized in that the recess is a groove (214a, 214b) of substantially annular shape, and axisymmetrical along the axis of revolution (300) of the component. 5. Component according to claim 4, characterized in that the recess is a groove (214a) opening at the first abutment surface (211; 111). 5 6. Component according to claim 5, characterized in that the length (L) of the groove (214a) is chosen such that it extends under at least 75% of the sealing surface (212; 102). 7. Component according to claim 5 or 6, characterized in that the groove (214a) has a thickness (ev) between 10 and 40% of the minimum thickness (es) of the zone carrying the sealing surface (212). 102). 10 8. Component according to claim 4, characterized in that the compressible volume (214) is a groove (214b) opening inside the end portion (210; 110). Component according to claim 8, characterized in that the length (L) of the groove (214a) is chosen such that it extends at least 75% of the sealing surface (212; 102). . 10. Component according to claim 8 or 9, characterized in that the groove (214a) has a depth (ev) of between 10 and 40% of the minimum thickness (es) of the zone carrying the sealing surface ( 212; 102). 11. Component according to any one of claims 2 or 3, characterized in that the volume (214) consists of an annular recess opening into the inside of the end portion (210; 110) and at the level of the first abutment surface (211; 111) partially filled by a reinforcement (215). 12. Component according to claim 11, characterized in that the length (L) of the annular recess is chosen so that it extends under at least 75% of the sealing surface (212; 102). 13. Component according to claim 11 or 12, characterized in that the reinforcement (215) has an axial Young's modulus greater than the Young's modulus of the material forming the drill string. 305 14. Component according to any one of claims 11 to 13, characterized in that the reinforcement (215) has a coefficient of friction at the level of the abutment surface at least 20% greater than that of the material constituting the liner. drilling. 15. Component according to any one of the preceding claims, characterized in that the end portion (210; 110) comprises an appendage (213) extending after the sealing surface (212; 102) to the first surface. stop (211; 111). 10 16. Component according to any one of the preceding claims, characterized in that the first end (200; 100) comprises a second abutment surface (201, 211; 101, 111) adapted to cooperate in clamping with an abutment surface ( 111, 101, 211, 201) of the second end (100; 200) of the other component.